SAMAY S24: a novel wireless 'online' device for real-time monitoring and analysis of volumetric capnography

Volumetric capnography (VCap) provides information about CO2 exhaled per breath (VCO2br) and physiologic dead space (VDphys). A novel wireless device with a high response time CO2 mainstream sensor coupled with a digital flowmeter was designed to monitor all VCap parameters online in rabbits (SAMAY S24).Ten New Zealand rabbits were anesthetized and mechanically ventilated. VCO2br corresponds to the area under the VCap curve. We used the modified Langley method to assess the airway VD (VDaw) and the alveolar CO2 pressure. VDphys was estimated using Bohr's formula, and the alveolar VD was calculated by subtracting VDaw from VDphys. We compared (Bland-Altman) the critical VCap parameters obtained by SAMAY S24 (Langley) with the Functional Approximation based on the Levenberg-Marquardt Algorithm (FA-LMA) approach during closed and opened chest conditions.SAMAY S24 could assess dead space volumes and VCap shape in real time with similar accuracy and precision compared to the 'offline' FA-LMA approach. The opened chest condition impaired CO2 kinetics, decreasing the phase II slope, which was correlated with the volume of CO2 exhaled per minute.

Older adults' subjective experiences of the COVID-19 outbreak and lockdown in Italy: A qualitative study

OBJECTIVE

To evaluate the subjective experience of the COVID-19 outbreak in healthy older adults and develop a model of the older population's psychological adaptation to the COVID-19 pandemic.

METHODS

A qualitative grounded theory approach was taken to the study design and analysis, using semi-structured interviews to collect data from 19 community-active Italian older people by telephone during the first wave of COVID-19 (May 2020).

RESULTS

The theory emerging from the study conceptualized the COVID-19 subjective experience in older people as an adjustment process to the disruption of habits, social contacts, and routines that prompted a meaning-making process to face this adverse experience. Three emergent categories included 'loss, uncertainty, and distress' as the psychological impact of the pandemic emergency, 'making sense of COVID-19' as a subjective sense-making process of the pandemic, and 'living with the pandemic' as agency and self-management within the pandemic experience. The resulting narratives encompassed themes, i.e. risk perception, representation of the self, connection with past-time memories, and compliance with safety measures.

CONCLUSION

The results have implications for designing effective messages to promote hope, social responsibility, and commitment in aging during the COVID-19 pandemic and for health workers who wish to support the psychological health of older adults.

Closeness to friends explains age differences in positive emotional experience during the lockdown period of COVID-19 pandemic

Background

Studies on age differences in emotional states during the COVID-19 pandemic showed that older adults experienced greater emotional wellbeing compared to younger adults. We hypothesized these age differences to be related to the perception of closeness to family/friends or the engagement in daily activities during the pandemic.

Aim

To investigate age differences in positive and negative emotional experiences and whether the perception of closeness to family/friends and the engagement in daily activities during pandemic explained such age-related differences.

Methods

Through a cross-sectional study, 1,457 adults aged 18–87 years old completed an online survey assessing positive and negative emotional experiences, the perception of more closeness to family/friends, and daily activities that participants started/re-started during the pandemic.

Results

Increasing age was associated with more positive and less negative emotional experiences. Age differences in positive emotional experience were explained by the perception of more closeness to friends and not by the engagement in daily activities. For negative emotional experience age, differences remained significant even after accounting for the perception of closeness to family/friends and engagements in daily activities.

Discussion

Older adults’ greater overall level of positive emotional experience was explained by their greater perception of more closeness to friends. We speculate that social closeness provides a coping mechanism to increase emotional wellbeing employed especially in older adults.

Conclusion

Our findings reinforce the link between perceived social closeness and emotional wellbeing especially in older adults. To cope with stressful situation, it is important to encourage older adults to increase the closeness to their social network.

Risk Perception in a Real-World Situation (COVID-19): How It Changes From 18 to 87 Years Old

Studies on age-related differences in risk perception in a real-world situation, such as the recent COVID-19 outbreak, showed that the risk perception of getting COVID-19 tends to decrease as age increases. This finding raised the question on what factors could explain risk perception in older adults. The present study examined age-related differences in risk perception in the early stages of COVID-19 lockdown, analyzing variables that can explain the differences in perception of risk at different ages. A total of 1,765 adults aged between 18 and 87 years old completed an online survey assessing perceived risk severity and risk vulnerability of getting COVID-19, sociodemographic status, emotional state, experience relating to COVID-19, and physical health status. Results showed that the older the participants, the lower the perceived vulnerability to getting COVID-19, but the higher the perceived severity. Different predictors explain the perception of risk severity and vulnerability at different ages. Overall, self-reported anxiety over the pandemic is a crucial predictor in explaining risk perceptions in all age groups. Theoretical and practical implications of the empirical findings are discussed.

Risk Perception in a Real-World Situation (COVID-19): How It Changes From 18 to 87 Years Old

Studies on age-related differences in risk perception in a real-world situation, such as the recent COVID-19 outbreak, showed that the risk perception of getting COVID-19 tends to decrease as age increases. This finding raised the question on what factors could explain risk perception in older adults. The present study examined age-related differences in risk perception in the early stages of COVID-19 lockdown, analyzing variables that can explain the differences in perception of risk at different ages. A total of 1,765 adults aged between 18 and 87 years old completed an online survey assessing perceived risk severity and risk vulnerability of getting COVID-19, sociodemographic status, emotional state, experience relating to COVID-19, and physical health status. Results showed that the older the participants, the lower the perceived vulnerability to getting COVID-19, but the higher the perceived severity. Different predictors explain the perception of risk severity and vulnerability at different ages. Overall, self-reported anxiety over the pandemic is a crucial predictor in explaining risk perceptions in all age groups. Theoretical and practical implications of the empirical findings are discussed.

The Early Impact of the Covid-19 Emergency on Mental Health Workers: A Survey in Lombardy, Italy

Lombardy was the epicenter of the Covid-19 outbreak in Italy, and in March 2020 the rapid escalation in cases prompted the Italian Government to decree a mandatory lockdown and to introduce safety practices in mental health services. The general objective of the study is to evaluate the early impact of the Covid-19 emergency and quarantine on the well-being and work practices of mental health service personnel and professionals. Data were collected through an online survey of workers and professionals working with people with mental health problems in Lombardy in several outpatient and inpatient services. Their socio-demographic characteristics, professional background, description of working conditions during lockdown and psychological distress levels were collected. All analyses were performed on a sample of 241. Approximately, 31% of the participants obtained a severe score in at least one of the burnout dimensions, 11.6% showed moderate or severe levels of anxiety, and 6.6% had a moderate or severe level of depression. Different work conditions and patterns of distress were found for outpatient service workers and inpatient service workers. The overall impact of the Covid-19 emergency on mental health workers' level of distress was mild, although a significant number of workers experienced severe levels of depersonalization and anxiety. More research is needed to assess specific predictive factors.

Development and validation of the mental health professional culture inventory

AIMS

No instrument has been developed to explicitly assess the professional culture of mental health workers interacting with severely mentally ill people in publicly or privately run mental health care services. Because of theoretical and methodological concerns, we designed a self-administered questionnaire to assess the professional culture of mental health services workers. The study aims to validate this tool, named the Mental Health Professional Culture Inventory (MHPCI). The MHPCI adopts the notion of 'professional culture' as a hybrid construct between the individual and the organisational level that could be directly associated with the professional practices of mental health workers.

METHODS

The MHPCI takes into consideration a multidimensional definition of professional culture and a discrete number of psychometrically derived dimensions related to meaningful professional behaviour. The questionnaire was created and developed by a conjoint Italian-Canadian research team with the purpose of obtaining a fully cross-cultural questionnaire and was pretested in a pilot study. Subsequently, a validation survey was conducted in northern Italy and in Canada (Montreal area, Quebec). Data analysis was conducted in different steps designed to maximise the cross-cultural adaptation of the questionnaire through a recursive procedure consisting of performing a principal component analysis (PCA) on the Italian sample (N = 221) and then testing the resulting factorial model on the Canadian sample (N = 237). Reliability was also assessed with a test-retest design.

RESULTS

Four dimensions emerged in the PCA and were verified in the confirmatory factor analysis: family involvement, users' sexuality, therapeutic framework and management of aggression risk. All the scales displayed good internal consistency and reliability.

CONCLUSIONS

This study suggests the MHPCI could be a valid and reliable instrument to measure the professional behaviour of mental health services workers. The content of the four scales is consistent with the literature on psychosocial rehabilitation, suggesting that the instrument could be used to evaluate staff behaviour regarding four crucial dimensions of mental health care.

Experiences of Mental Healthcare Reported by Individuals Diagnosed with Bipolar Disorder: An Italian Qualitative Study

This qualitative study explores experiences of mental health care by nine Italian users with a diagnosis of bipolar disorder. The findings from semi-structured interviews carried by professional researchers highlighted the following themes: mixed feelings about the diagnosis; lack of access to psychological interventions despite preferences of users; positive view of peer support, job as a safe haven, traumatic experiences of compulsory hospital admissions; need for crisis interventions as alternative to hospital admission. Most users' views look in accordance with evidence-based recommendations seldom implemented in practice. Future research directions, implications of users' expectations and experiences for service planning and quality improvement, are presented and discussed in the light of the qualitative available literature.

Do people with bipolar disorders have access to psychosocial treatments? A survey in Italy

BACKGROUND

Several guidelines consider psychosocial treatments an essential component of clinical management of bipolar disorders in addition to drug therapy. However, to what extent such interventions are available in everyday practice to the average patient attending mental health services is not known.

AIMS

This study aims to investigate access of people with bipolar disorders to psychosocial treatments in a community-based care system.

METHOD

Information on care delivery and service utilization were retrieved from the psychiatric database of Lombardy, Italy, covering a population of 9,743,000, for all adults who had at least one contact in 2009 with psychiatric services. Rates of patients with a diagnosis of bipolar disorder who had access to individual psychotherapy, couple/family therapy, group psychotherapy and family interventions were calculated and compared to patients with schizophrenia and depression.

RESULTS

A total of 8,899 subjects with bipolar disorder had been in contact with psychiatric services, corresponding to a treated annual prevalence rate of 1.1‰. More than 80% of patients were treated in community settings. Rates of patients receiving structured psychosocial treatments ranged from 0.7% for couple/family therapy to 6.1% for individual psychotherapy. No differences with patients with schizophrenia and depression were found. Patients with schizophrenia received more interventions labeled as rehabilitation.

CONCLUSION

Few people with bipolar disorders had access to psychosocial treatments. Even in a well-developed system of community care, offer of psychosocial interventions for bipolar disorders is inadequate. This issue should be a target for future research on dissemination and implementation strategies.

An evidence map of psychosocial interventions for the earliest stages of bipolar disorder

Depression, schizophrenia, and bipolar disorder are three of the four most burdensome problems in people aged under 25 years. In psychosis and depression, psychological interventions are effective, low-risk, and high-benefit approaches for patients at high risk of first-episode or early-onset disorders. We review the use of psychological interventions for early-stage bipolar disorder in patients aged 15-25 years. Because previous systematic reviews had struggled to identify information about this emerging sphere of research, we used evidence mapping to help us identify the extent, distribution, and methodological quality of evidence because the gold standard approaches were only slightly informative or appropriate. This strategy identified 29 studies in three target groups: ten studies in populations at high risk for bipolar disorder, five studies in patients with a first episode, and 14 studies in patients with early-onset bipolar disorder. Of the 20 completed studies, eight studies were randomised trials, but only two had sample sizes of more than 100 individuals. The main interventions used were family, cognitive behavioural, and interpersonal therapies. Only behavioural family therapies were tested across all of our three target groups. Although the available interventions were well adapted to the level of maturity and social environment of young people, few interventions target specific developmental psychological or physiological processes (eg, ruminative response style or delayed sleep phase), or offer detailed strategies for the management of substance use or physical health.

Do patients with bipolar disorders receive evidence-based psychosocial interventions? a survey in Italy

Introduction

Research evidence on bipolar disorder supports the importance of patients’ active role to improve outcome and the efficacy of a number of psychosocial interventions. The lower cost and potential ease of dissemination of group psychoeducation suggest that this should be a first line approach, with more complex interventions, requiring highly specialized skills, reserved to selected patients. However, to what extent research models can be transferred to everyday practice remains to be seen.

Objectives

To explore the delivery of psychosocial interventions to bipolar disorders patients in routine mental health care.

Aims

To estimate the treated prevalence of bipolar disorders in Milan and to collect data about the variety of psychosocial interventions patients received by mental health services.

Methods

A survey of psychosocial interventions received by bipolar patients in three mental health services of Milan (catchment area 867,000 inhabitants) was conducted in 2009. Data from the Regional Mental Health Information System were retrieved to calculate the number of patients involved in psychosocial interventions and the kind of intervention provided.

Results

The treated prevalence rate was low, showing a probable treatment gap. Only 20% of 636 bipolar patients received at least one psychosocial intervention. The interventions provided were: family psychoeducation (3,8%), individual social skills training (11,5%), group social skills training (1,4%), and relatives group (3,0%).

Conclusions

Few bipolar patients receive psychosocial interventions in the MHS of Milan. Moreover, the interventions received were not specifically designed for bipolar disorder. Treatment gap could be reduced providing psychoeducation especially designed for bipolar patients.

[Adoptive parental couple: a pilot study]

International adoption is a phenomenon in constant growth, involving over one hundred countries. In Italy there are approximately two thousand adoptions of foreign minors per year. The needs demonstrated by the families adopting these children, sometimes bearing complex problems, have led to the offer of a combined medical and psychological intervention oriented towards a global and integrated approach to the needs of a family that is changing with the arrival of a new member. Therefore, a clinical evaluation of the health status of the child recently arrived in Italy, targeted at identifying the presence of medical or psychological conditions, is performed during the day spent at the day hospital. The authors present data and considerations emerging from their ongoing experience, which has already involved 113 children and 89 families. The majority of the children evaluated so far show acute physical conditions, requiring major attention and support from their parents. The authors believe that in order to organize an adequate intervention it is useful to consider the parents of these children as caregivers. The function of caregiver is identified at three levels: the care of the child as son/daughter (typical of the parental function), the care of the problems deriving from the specific preadoption experience that accompany the child in the new family, and the care of the sick child. The authors deem that the combined medical and psychological intervention adopted at present with these families constitutes a useful support to the caregiver function.

PACAP in developing sensory and peripheral organs of the zebrafish, Danio rerio

The anatomical distribution of PACAP-like immunoreactivity was investigated in sensory and peripheral organs of the zebrafish, Danio rerio, during the pharyngula, hatching and larval periods, by using indirect immunofluorescence methods. First PACAP-like immunoreactive (ir) elements appeared during the pharyngula period, at 24 hours post fertilization (hpf), within the most superficial layer of the retina and the dorsal aorta. At 48 hpf, additional ir cells were found in the olfactory placode and esophagus. At 72 hpf (hatching period), PACAP-like immunoreactivity was first detected in the ganglion cell layer of the retina, the otic sensory epithelium, pharyngeal arches, swim bladder and pancreatic progenitor cells. During day 5 of larval development, new groups of ir cells appeared in the liver, whereas no ir elements were observed in the olfactory placode. Subsequently, at day 13 of larval development, additional ir elements were found for the first time in some gut epithelial cells while those previously observed in the retina and otic sensory epithelium were absent. The transient expression of PACAP-like ir material in sensory organs suggests that the peptide could be implicated in neurotrophic activities and neurosensorial connections in the migration and/or differentiation processes. The appearance of PACAP-like ir elements in peripheral organs at different developmental stages, indicates that this peptide could be involved in the control of more specific functions as soon as these peripheral structures begin to operate.

Jun localization in cytosolic and nuclear compartments in brain-pituitary system of the frog, Rana esculenta: an analysis carried out in parallel with GnRH molecular forms during the annual reproductive cycle

The presence of c-jun like mRNA was assessed in the brain of the frog, Rana esculenta, during the annual sexual cycle. In parallel, Jun protein and GnRH molecular form (mammalian and chicken II also indicated as GnRH1 and GnRH2, respectively) activity was studied in order to establish possible relationships. Northern blot analysis of total RNA reveals the presence of a 2.7 kb c-jun-like mRNA. Western blots, carried out on cytoplasmic and nuclear protein extracts, show the presence of Jun immunoreactive band of 39 kDa in brain and pituitary. Fluctuations of c-jun-like mRNA and Jun immunoreactive protein (cytoplasmic and nuclear) levels in brains during the year indicate relationships among transcription, translation, and nuclear activity. In particular, mRNA levels increase gradually from September until November when Jun protein concentration peaks in cytosolic extracts. Conversely, the nuclear protein reaches highest concentration in July when the cytosolic level shows low values. Immunocytochemical studies confirm the presence of Jun immunoreactivity in both cytoplasmic and nuclear compartments of several brain areas, including those primarily involved in gonadotropin discharge (e.g., anterior preoptic area and preoptic nucleus). GnRH molecular forms and Jun are colocalized in anterior preoptic area and preoptic nucleus. Moreover, during the period characterized by GnRH release, Jun levels strongly decrease in nuclei. Finally, we show that treatments with a GnRH analog (buserelin, Hoechst, Frankfurt) increase Jun levels in brain nuclear extracts.

Immunohistochemical localization of 3 beta-hydroxysteroid dehydrogenase and 5 alpha-reductase in the brain of the African lungfish Protopterus annectens

The localization of the enzymes responsible for the biosynthesis of neurosteroids in the brain of dipnoans has not yet been determined. In the present study, we investigated the immunohistochemical distribution of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and 5 alpha-reductase (5 alpha-R) in the brain and pituitary of the African lungfish Protopterus annectens by using antibodies raised against type I human 3 beta-HSD and type I human 5 alpha-R. The 3 beta-HSD and 5 alpha-R immunoreactivities were detected in cell bodies and fibers located in the same areas of the lungfish brain, namely, in the pallium, thalamus, hypothalamus, tectum, and periaqueductal gray. Identification of astrocytes, oligodendrocytes, and neurons with antisera against glial fibrillary acidic protein, galactocerebroside and neurofilaments revealed that, in the lungfish brain, 3 beta-HSD immunolabeling is expressed exclusively by neurons, whereas the 5 alpha-R-immunoreactive material is contained in both neurons and glial cells. In the pituitary gland, 3 beta-HSD- and 5 alpha-R-like immunoreactivity was localized in both the pars distalis and the pars intermedia. The present study provides the first immunocytochemical mapping of two key steroidogenic enzymes in the brain and pituitary of a lungfish. These data strongly suggest that neurosteroid biosynthesis occurs in the brain of fishes, as previously shown for amphibians, birds, and mammals.

Immunohistochemical localization of atrial natriuretic factor and autoradiographic distribution of atrial natriuretic factor-binding sites in the brain of the cave salamander Hydromantes genei (Amphibia, Plethodontidae)

The distribution of atrial natriuretic factor (ANF)-like immunoreactivity in the central nervous system of the cave salamander Hydromantes genei (Amphibia, Plethodontidae) was investigated by using antisera raised against rat and human ANF(1-28). Concurrently, the location of ANF-binding sites was determined by autoradiography, using radioiodinated human ANF(1-28) as a tracer. In several regions of the brain, including the olfactory bulb, the preoptic area, the ventral thalamus, the tectum of the mesencephalon, and the choroid plexuses inside the ventricles, a good correlation was observed between the distribution of ANF-immunoreactive elements and the location of ANF-binding sites. Mismatching was found in the habenular nucleus, the commissura habenularis, the fasciculum retroflexus, and the interpeduncular nucleus, which contained high levels of binding sites but were devoid of ANF-immunoreactive structures. In contrast, a few other regions, such as the pineal gland and the subcommissural organ, showed a high concentration of ANF-like immunoreactivity but did not contain ANF-binding sites. This study provides the first localization of ANF-like immunoreactivity and ANF-binding sites in the brain of an urodele amphibian. The results show that the ANF peptidergic system in the cave salamander has an organization more simple than the organizations described for the brain of frog or other vertebrates. This feature is probably related to the expression of highly pedomorphic characters in plethodontids. The anatomical distribution of ANF-immunoreactive elements and ANF-binding sites suggests that ANF-related peptides may act as hypophysiotropic hormones as well as neurotransmitters and/or neuromodulators in the salamander brain.

Pituitary adenylate cyclase-activating polypeptide and its receptors in amphibians

Pituitary adenylate cyclase-activating polypeptide (PACAP), a novel peptide of the secretin/glucagon/vasoactive intestinal polypeptide superfamily, has been initially characterized in mammals in 1989 and, only 2 years later, its counterpart has been isolated in amphibians. A number of studies conducted in the frog Rana ridibunda have demonstrated that PACAP is widely distributed in the central nervous system (particularly in the hypothalamus and the median eminence) and in peripheral organs including the adrenal gland. The cDNAs encoding the PACAP precursor and 3 types of PACAP receptors have been cloned in amphibians and their distribution has been determined by in situ hybridization histochemistry. Ontogenetic studies have revealed that PACAP is expressed early in the brain of tadpoles, soon after hatching. In the frog Rana ridibunda, PACAP exerts a large array of biological effects in the brain, pituitary, adrenal gland, and ovary, suggesting that, in amphibians as in mammals, PACAP may act as neurotrophic factor, a neurotransmitter and a neurohormone.

Ontogeny of pituitary adenylate cyclase-activating polypeptide (PACAP) in the frog (Rana ridibunda) tadpole brain: immunohistochemical localization and biochemical characterization

The anatomic distribution and biochemical characteristics of the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) were investigated in the central nervous system of the frog, Rana ridibunda, during development. Three to four days after hatching, at stages IV-VII, PACAP-immunoreactive perikarya were detected in the dorsal thalamus within the anterior ventral area, and a few fibers were found in the medial pallium. Positive cell bodies were first observed in the hypothalamus at stages VIII-IX, at the level of the dorsal and ventral infundibular nuclei. In these regions, the number of positive perikarya increased during ontogeny. In tadpoles, during the mid- and late premetamorphosis, a more complex organization of the PACAP-immunoreactive system was found in the thalamus with the appearance, at stages IX-XII, of two additional groups of positive neurons in the ventrolateral area and posterocentral nucleus. At stages XIII-XVIII of larval development and subsequent larval stages, PACAP-immunoreactive fibers were found in the median eminence. In newly metamorphosed animals, several additional groups of positive perikarya appeared in the medial pallium, the preoptic nucleus, the torus semicircularis, the tegmentum of the mesencephalon, and the cerebellum. The immunoreactive peptide contained in the tadpole brain was characterized by high performance liquid chromatography analysis combined with radioimmunoassay quantification. At all stages investigated, the predominant form of PACAP-immunoreactive material coeluted with synthetic frog PACAP38. The occurrence of PACAP soon after hatching indicates that the peptide may exert neurotrophic activities. The existence of immunoreactive elements in several thalamic regions at mid- and late premetamorphic stages suggests that PACAP may act as a neurotransmitter, neuromodulator, or both, during ontogenesis. Finally, the presence of PACAP-immunoreactive perikarya in hypothalamic nuclei and nerve fibers in the median eminence supports the view that PACAP may play a role in the control of pituitary hormone secretion during larval development.

Organization of vasoactive intestinal peptide-like immunoreactive system in the brain, olfactory organ and retina of the zebrafish, Danio rerio, during development

The localization of vasoactive intestinal peptide (VIP)-like immunoreactivity was investigated in the brain, olfactory system and retina of the zebrafish, Danio rerio, during development and in juvenile specimens, by using the indirect immunofluorescence and the peroxidase-antiperoxidase methods. In 24 h post fertilization (hpf) embryos, VIP-like immunoreactive cells were present in the olfactory pit, the retina, and several regions of the brain, including the dorsal telencephalon, the diencephalon, the tegmentum of the mesencephalon, the caudal rhombencephalon and the anterior pituitary. In 48 hpf embryos, additional VIP-like immunoreactive cell bodies were found in the ventral telencephalon, whereas in the diencephalon VIP-like immunopositive cells were more concentrated within the ventro-caudal hypothalamus. During the 7 day larval period, a dense plexus of VIP-like immunoreactive fibers first appeared in the olfactory bulbs. In 15-day-old larvae, two new groups of positive cells were observed in the periventricular preoptic nucleus and in the dorsal rhombencephalon. In 1 month/2 months old animals, VIP-like immunoreactive elements were confined to the olfactory organ, the olfactory bulbs, the periventricular preoptic nucleus and the pituitary, pars distalis. At 3 months stage, a large number of cells was observed in the periventricular preoptic nucleus. Western immunoblot analysis confirmed that VIP-like peptides, with molecular weight similar to that of synthetic VIP, are present early during the development of zebrafish. These results show that VIP-like immunoreactive structures appear early during ontogeny both in the olfactory pit, retina and brain. Transient expression of positive cells was found in the retina, telencephalon, diencephalon and brainstem. The location of VIP-like immunoreactivity indicates that, during development, VIP could be involved in several neuromodulatory functions, including the processing of visual and olfactory informations, as well as growth or survival promotion activities. The presence of VIP-like immunopositive cells in the pituitary, pars distalis, suggest that, during development, VIP may influence the secretion of pituitary hormones.

In the african lungfish Met-enkephalin and leu-enkephalin are derived from separate genes: cloning of a proenkephalin cDNA

A full-length proenkephalin cDNA (accession number: AF232670) was cloned from an African lungfish (Protopterus annectens) brain cDNA library. The 1,351-bp African lungfish proenkephalin contains an open reading frame that codes 266 amino acids and a stop codon. Within the sequence of lungfish proenkephalin there are 5 pentapeptide opioid sequences (all YGGFM), 1 octapeptide opioid sequence (YGGFMRSL) and 1 heptapeptide opioid sequence (YGGFMGY). A Leu-enkephalin sequence was conspicuously absent in lungfish proenkephalin. These results, coupled with observations on the organization of amphibian proenkephalin and mammalian proenkephalin, indicate that among the Sarcopterygii (lobed finned fish and tetrapods), the appearance of a Leu-enkephalin sequence in proenkephalin may have evolved in either the ancestral amniotes or the ancestral mammals, but not earlier in sarcopterygian evolution. Furthermore, the detection of neurons in the lungfish CNS that are only immunopositive for Met-enkephalin, coupled with earlier anatomical studies on the presence of neurons in the lungfish CNS that are only immunopositive for Leu-enkephalin, indicates that a Leu-enkephalin-coding opioid gene must be present in the CNS of the lungfish. This gene may be the lungfish form of prodynorphin. Given the phylogenetic position of the lungfish in vertebrate evolution, the putative Leu-enkephalin-coding gene must have evolved in the ancestral sarcopterygian vertebrates, or in the ancestral gnathostomes. The apparent slow rate of lungfish evolution makes these organisms interesting models for investigating the evolution of the opioid/orphanin gene family.

In vivo evidence for the production of sulfated steroids in the frog brain

It is well established that sulfated neurosteroids are potent regulators of neuronal activity but the biosynthesis of sulfate esters of steroids in the central nervous system (CNS) has received little attention. In particular, the localization of hydroxysteroid sulfotransferase (HST), the enzyme which is responsible for the formation of sulfated steroids, has never been determined in the brain. We took advantage of the availability of an antiserum raised against rat liver HST to investigate the distribution of this enzyme in the CNS of the frog Rana ridibunda. Two populations of HST-positive neurons were localized in the anterior preoptic area and the magnocellular nucleus of the hypothalamus. Numerous HST-immunoreactive fibers were visualized throughout the telencephalon and the diencephalon. Reversed-phase high performance liquid chromatography (HPLC) analysis of frog telencephalon and hypothalamus extracts combined with radioimmunoasssay (RIA) detection showed the presence of substantial amounts of DHEAS-immunoreactive material which coeluted with synthetic DHEAS. The concentrations of DHEAS detected in the telencephalon and hypothalamus were respectively eight and five times higher than in the serum. The present study demonstrates the occurrence of HST-immunoreactive material in neurons of the frog telencephalon and diencephalon. This report also provides evidence for the presence of HST bioactivity, in vivo, in the frog brain.

Distribution of GAD-immunoreactive neurons in the diencephalon of the african lungfish Protopterus annectens: colocalization of GAD and NPY in the preoptic area

The distribution of GABAergic neurons was investigated in the diencephalon of the African lungfish, Protopterus annectens, by using specific antibodies directed against glutamic acid decarboxylase (GAD). A dense population of immunoreactive perikarya was observed in the periventricular preoptic nucleus, whereas the caudal hypothalamus and the dorsal thalamus contained only scattered positive cell bodies. Clusters of GAD-positive cells were found in the intermediate lobe of the pituitary. The diencephalon was richly innervated by GAD-immunoreactive fibers that were particularly abundant in the hypothalamus. In the periventricular nucleus, GAD-positive fibers exhibited a radial orientation, and a few neurons extended processes toward the third ventricle. More caudally, a dense bundle of GAD-immunoreactive fibers coursing along the ventral wall of the hypothalamus terminated into the median eminence and the neural lobe of the pituitary. Double-labeling immunocytochemistry revealed that GAD and neuropeptide tyrosine (NPY)-like immunoreactivity was colocalized in a subpopulation of perikarya in the periventricular preoptic nucleus. The proportion of neurons that coexpressed GAD and NPY was higher in the caudal region of the preoptic nucleus. The distribution of GAD-immunoreactive elements in the diencephalon and pituitary of the African lungfish indicates that GABA may act as a hypophysiotropic neurohormone in Dipnoans. The coexistence of GAD and NPY in a subset of neurons of the periventricular preoptic nucleus suggests that GABA and NPY may interact at the synaptic level.

Distribution of vasoactive intestinal peptide-like immunoreactivity in the brain and pituitary of the frog (Rana esculenta) during development

The localization of vasoactive intestinal peptide (VIP)-like immunoreactive (ir) elements was investigated in the brain of the anuran amphibian, Rana esculenta, during development. Using an antiserum raised against the porcine VIP, ir cell bodies and fibers were observed in the forebrain of tadpoles a few days after hatching. During early premetamorphosis, ir perikarya were distributed in the ventral infundibular nucleus of the hypothalamus and in the posterocentral nucleus of the thalamus. Labeled fibers were detected in the olfactory bulbs and in the hypothalamus. In these larvae, furthermore, several VIP-ir cells were found in the pars distalis of the pituitary and there were ir fibers in the pars nervosa. In tadpoles at stages VIII-IX, a new group of VIP-labeled neurons was observed in the dorsal part of the infundibular nucleus. In other brain regions, the distribution of the immunoreactivity was similar to that described in the earliest stages, i.e., IV-VII. During mid-premetamorphosis, stages X-XII of development, an additional set of ir perikarya appeared in the ventrolateral area of the thalamus. During late premetamorphosis, stages XIII-XVIII, the organization of VIP-like immunoreactivity was more complex and its distribution more widespread. Two new groups of ir cell bodies appeared, one in the preoptic nucleus and another in the anteroventral area of the thalamus, and for the first time, VIP immunoreactivity was observed in the median eminence. This distribution pattern persisted through to the prometamorphic, four-limb stage. Strikingly, no VIP-ir elements were observed anywhere in the mid- and hindbrain. The present results indicate that a VIP-like ir peptide may be involved in the processing of olfactory information or may act as a neurohormone, hypophysiotropic factor, and neuromodulator in the brain of R. esculenta during development.

Identification of an urotensin I-like peptide in the pituitary of the lungfish Protopterus annectens: immunocytochemical localization and biochemical characterization

In the present study we have investigated the localization and biochemical characteristics of urotensin I (UI)-like and urotensin II (UII)-like immunoreactive peptides in the central nervous system (CNS) and pituitary of the lungfish, Protopterus annectens, by using antisera raised against UI from the white sucker Catostomus commersoni and against UII from the goby Gillichythys mirabilis. UI-like immunoreactive material was found within the melanotrope cells of the intermediate lobe of the pituitary. By contrast, no UI-immunoreactive structures were found in the brain. No UII-like peptides structurally similar to goby UII were found in the brain and pituitary of P. annectens. The UI-immunoreactive material localized in the pituitary was characterized by combining reversed-phase high-performance liquid chromatography (HPLC) analysis and radioimmunological detection. The UI-like immunoreactivity contained in a pituitary extract eluted as a single peak with a retention time intermediate between those of sucker UI and rat corticotropin-releasing factor (CRF). Control tests on adjacent sections of pituitary showed that the UI antiserum cross-reacted with the frog skin peptide sauvagine, but lungfish UI did not co-elute with synthetic sauvagine on HPLC. On the contrary, no cross-reaction was observed between the UI antiserum and CRF or alpha-melanocyte-stimulating hormone (alpha-MSH). The occurrence of an UI-like peptide in the intermediate lobe of the pituitary of P. annectens suggests that, in lungfish, this peptide may act as a classic pituitary hormone or may be involved in the control of melanotrope cell secretion.

Fos localization in cytosolic and nuclear compartments in neurones of the frog, Rana esculenta, brain: an analysis carried out in parallel with GnRH molecular forms

C-fos activity was determined in the brain of the frog, Rana esculenta, during the annual sexual cycle. The localization of GnRH molecular forms (mammalian- and chicken-GnRHII) was also carried out to determine whether or not the proto-oncogene and the peptides showed a functional relationship. Northern blot analysis of total RNA revealed the presence of a single strong signal of c-fos like mRNA of 1.9 Kb during February and April. This was followed by expression of c-Fos protein (Fos) in several brain areas during March and July shown by immunocytochemistry. In particular, the olfactory region, the lateral and medial pallium, the nucleus lateralis septi, the ventral striatum, the caudal region of the anterior preoptic area, the suprachiasmatic nucleus, the ventral thalamus, tori semicircularis and ependymal layers of the tectum were immunostained. There was no overlap between Fos immunoreactive perikarya and GnRH immunoreactive perikarya (e.g. gonadotrophin-releasing hormone (GnRH) in the rostral part and Fos in the caudal region of the anterior preoptic area). Interestingly, a cytoplasmic localization of Fos was also observed by immunocytochemistry and gel retardation experiments supported this observation. Cytoplasmic extracts from September-October animals bound the AP1 oligonucleotide. The complex was not available in the nuclear extracts from the same preparation, suggesting that, besides Fos, Jun products were also present. Conversely, nuclear but not cytosolic binding was detected in the brain of animals collected in July. In conclusion, we show that Fos and GnRH activity does not correlate in the frog brain and, for the first time in a vertebrate species, we give evidence of a cytoplasmic AP1 complex in neuronal cells.

Molecular cloning of the cDNAs and distribution of the mRNAs encoding two somatostatin precursors in the African lungfish Protopterus annectens

The occurrence of two somatostatin precursors, PSS1 and PSS2, yielding S-14 (SS1) and the variant [Pro2, Met13]S-14 (SS2), has been recently reported in the frog Rana ridibunda. The evolutionary significance of frog PSS2 is unclear because its sequence exhibits very little similarity with other known vertebrate somatostatin precursors. In the present study, we report on the characterization of two somatostatin precursor cDNAs from the brain of the African lungfish Protopterus annectens. One of the cDNAs encodes a 115-amino-acid protein that contains the SS1 sequence at its C-terminal extremity and thus is clearly homologous to PSS1. Comparison with other vertebrate PSS1 showed that lungfish PSS1 is more closely related to PSS1 from tetrapods than to PSS1 from fish. The other cDNA encodes a 109-amino-acid protein that contains a somatostatin variant [Pro2]S-14 at its C-terminal extremity. Sequence analysis of this second precursor indicated that it is the lungfish counterpart of frog PSS2. Northern blot analysis showed that lungfish PSS1 mRNA is widely distributed in the central nervous system and in peripheral organs, including the pancreas and gastrointestinal tract. In contrast, PSS2 mRNA was primarily found in the central nervous system but not in the pancreas or gut. In situ hybridization studies showed that the two genes are differentially expressed in various regions of the lungfish brain. The present data indicate that the PSS2 gene, initially discovered in frog, appeared early in vertebrate evolution, before the emergence of the tetrapod lineage. The recent isolation of a [Pro2]S-14 variant in the sturgeon, whose sequence is identical to that of lungfish SS2, suggests that the PSS2 gene may actually be present in the genome of all Osteichthyii.

[Study of the relaxation phase of the right ventricle]

The purpose of our study was to investigate the existence or not of an isovolumic relaxation period in the right ventricle in experimental animals with normal pressures in the pulmonary artery. Right and left ventricular pressures, pulmonary and aortic pressures (microtransducers), pulmonary flow, ventricular diameters (sonomicrometer), were recorded at the same time, in 10 sheep anesthetized intravenously with pentobarbital. We obtained "off line" the first ventricular pressures derivative, the ventricular volumes and the pressure-volume loops of both ventricles. The minimum systolic right ventricular volume coincided with 0 pulmonary flow, and both with a diastolic pressure value of 0-5 mmHg in that ventricle. Once the minimum systolic volume was reached, a rapid increase of the right ventricular volume started. The right ventricular pressure-volume loop, unlike the left ventricular one, adopted a non-rectangular shape. The right ventricular ejection period lasted until the beginning of the next filling phase. We concluded that there is no right ventricular isovolumic relaxation period.

[The characteristics proper of the cardiac cycle phases of the right ventricle]

AIMS

The purpose of our study was to define at physiological conditions, the existence or not of an isovolumic relaxation phase in the right ventricle and its ejective phase properties.

MATERIAL AND METHODS

Right and left ventricular pressures, pulmonary and aortic pressures, pulmonary flow and ventricular diameters by sonomicrometry were measured in nine anesthetized sheep. The first ventricular pressure derivative, ventricular volumes, and the right and left pressure-volume loops, were calculated "off line". An abrupt preload reduction was generated by a posterior vena caval occlusion.

RESULTS

Right ventricle showed an ejection phase which can be subdivided in two phases (early and late). The end of the ejection phase was established by the temporal coincidence of the zero pulmonary flow, the minimum systolic value of the right ventricular volume and a right ventricular pressure of 0-4 mmHg. The time between the beginning of the ejection phase and: a) the end of systole; b) the negative peak of the first derivative of ventricular pressure and c) the end of ejection, were different for the right ventricle (67 +/- 15 ms, 274 +/- 30 ms, 412 +/- 33 ms, respectively), meanwhile the left ventricle showed the following values: 204 +/- 33 ms, 262 +/- 23 ms, 266 +/- 24 ms, respectively.

CONCLUSIONS

Right ventricle exhibits a long lasting ejection phase which can be subdivided in two phases, spreading at the beginning of the next filling phase. This fact allows us to affirm that right ventricle does not show an isovolumic relaxation phase in comparison to left ventricle.

Characterization of bradykinin-related peptides generated in the plasma of six sarcopterygian species (African lungfish, amphiuma, coachwhip, bullsnake, gila monster, and Gray's monitor)

Incubation of heat-denatured plasma from six species occupying different evolutionary positions within the Sarcopterygian lineage [the dipnoan, Protopterus annectens (African lungfish); the urodele, Amphiuma tridactylum (three-toed amphiuma); the colubrid snakes, Pituophis melanoleucus sayi (bullsnake) and Masticophis flagellum (coachwhip); and the lizards Heloderma suspectum (Gila monster) and Varanus Grayi (Gray's monitor)] with trypsin generated bradykinin-related peptides that were detected by radioimmunoassay using an antiserum raised against mammalian bradykinin (BK). The peptides were purified by HPLC and their primary structures were established as lungfish [Tyr1,Gly2,Ala7,Pro8]BK, amphiuma [Phe1,Ile2, Leu5]BK, bullsnake and coachwhip [Val1,Thr6]BK, Gila monster [Leu2, Thr6]BK, and Gray's monitor [Thr6]BK. Monitor BK is identical to the peptide generated in turtle and alligator plasma and coachwhip/bullsnake BK shows one amino acid substitution (Ala1 --> Val) compared with the peptide generated in the plasma of the python. The data provide further evidence for the widespread occurrence of a kallikrein-kininogen system in nonmammalian vertebrates but indicate that the primary structure of BK has been poorly conserved during evolution.

Autoradiographic distribution of neuropeptide tyrosine binding sites in the brain of the African lungfish, Protopterus annectens

The distribution of neuropeptide tyrosine (NPY) binding sites in the brain of the African lungfish, Protopterus annectens, was studied by autoradiography using radioiodinated NPY as a tracer. The highest concentrations of binding sites were found in the dorsal and intermediate parts of the medial pallium, the dorsal pallium, and in the medial and lateral subpallium. These observations, together with the finding of a moderate density of binding sites in the olfactory bulbs, suggest that NPY may be involved in the processing of olfactory information and/or neuromodulation of limbic activities. High densities of binding sites were also found in several rhombencephalic nuclei, including the nucleus fascicoli solitarii, the nucleus motorius nervi vagi, the spinal motor column and all components of the reticular formation, indicating that NPY may play a role in the regulation of neurovegetative functions. Concurrently, the presence of high concentrations of binding sites in the hypophysis suggests that, in the lungfish, NPY may exert a direct control of pituitary hormone secretion.

Immunocytochemical localization of enkephalins in the brain of the African lungfish, Protopterus annectens, provides evidence for differential distribution of Met-enkephalin and Leu-enkephalin

The distribution of various opioid peptides derived from proenkephalin A and B was studied in the brain of the African lungfish Protopterus annectens by using a series of antibodies directed against mammalian opioid peptides. The results show that both Metenkephalin- and Leu-enkephalin-immunoreactive peptides are present in the lungfish brain. In contrast, enkephalin forms similar to Met-enkephalin-Arg-Phe, or Met-enkephalin-Arg-Gly-Leu, as well as mammalian alpha-neoendrophin, dynorphin A (1-8), dynorphin A (1-13), or dynorphin A (1-17) were not detected. In all major subdivisions of the brain, the overwhelming majority of Met-enkephalin- and Leu-enkephalin-immunoreactive cells were distinct. In particular, cell bodies reacting only with Leu-enkephalin antibodies were detected in the medial subpallium of the telencephalon, the griseum centrale, the reticular formation, the nucleus of the solitary tract, and the visceral sensory area of the rhombencephalon. Cell bodies reacting only with Met-enkephalin antibodies were found in the lateral subpallium of the telencephalon, the caudal hypothalamus, and the tegmentum of the mesencephalon. The preoptic periventricular nucleus of the hypothalamus exhibited a high density of Metenkephalin-immunoreactive neurons and only a few Leu-enkephalin-immunoreactive neurons. The distribution of Met-enkephalin- and Leu-enkephalin-immunoreactive cell bodies and fibers in the lungfish brain showed similarities to the distribution of proenkephalin A-derived peptides described previously in the brain of land vertebrates. The presence of Met-enkephalin- and Leu-enkephalin-like peptides in distinct regions, together with the absence of dynorphin-related peptides, suggests that, in the lungfish, Met-enkephalin and Leu-enkephalin may originate from distinct precursors.

Organization of atrial natriuretic factor-like immunoreactive system in the brain of the frog Rana esculenta during development

Immunocytochemical distribution of the atrial natriuretic factor (ANF) has been studied in the brain and pituitary of the anuran Rana esculenta during development and in juvenile animals. Using human ANF and rat alpha-ANF antisera, immunoreactive cell bodies and nerve fibers were revealed in stage II-III tadpoles and in successive larval stages. Soon after hatching, stages II-III, the ANF-like-immunoreactive elements were confined to the preoptic area-median eminence complex. During successive stages of development, new groups of ANF-immunoreactive cell bodies appeared. In larval stage VI, immunoreactive perikarya were found in the rostral part of the anteroventral area of the thalamus and numerous ANF-like-immunoreactive cells appeared in the pars distalis of the pituitary. In larval stages XIV and XVIII, the distribution of ANF immunoreactivity was virtually similar. The ANF-immunoreactive cells in the preoptic nucleus and in the pituitary pars distalis were comparatively more abundant than in stage VI. During the metamorphic climax (stages XXI-XXII), a new group of ANF-immunoreactive cell bodies appeared in the rostral part of the ventrolateral area of the thalamus. During this stage, ANF-immunoreactive fiber projections were found in the pars intermedia for the first time. However, the pars distalis cells were very weakly immunofluorescent. The pattern of ANF immunoreactivity in the brain of juvenile animals was very similar to that described for stages XXI and XXII, whereas the pars distalis cells showed no immunoreactivity. It is conceivable that, early during development, ANF-related peptides may be involved in the regulation of pituitary secretion by means of autocrine mechanisms or may act as a classic pituitary hormone.

Distribution of somatostatin-like immunoreactivity in the brain of the frog, Rana esculenta, during development

The anatomical distribution of somatostatin-like immunoreactivity in the central nervous system of the frog, Rana esculenta, during development and in juvenile specimens was investigated by indirect immunofluorescence. Soon after hatching, at stages II-III, somatostatin-like immunoreactive structures were found in the preoptic-median eminence complex. In stage VI tadpoles, new groups of immunopositive perikarya and nerve fibers appeared in the diencephalon, within the ventral infundibular nucleus and in the ventral area of the thalamus, as well as in the medial pallium. In stages XII-XIV of development, immunopositive perikarya were also present in the dorsal infundibular nucleus of the hypothalamus and ventrolateral area of the thalamus. A small group of somatostatin-like immunoreactive neurons appeared in the posteroventral nucleus of the rhombencephalon. However, these neurons were not seen in later stages of development. Tadpoles in stages XVIII, XXI-XXII and in juveniles were characterized by a wider distribution of immunoreactive cell bodies and fibers in the pallium. New groups of immunoreactive neurons were found in the dorsal and lateral pallium. The presence of positive perikarya in the lateral pallium is a transient expression found only in these stages. The organization of the somatostatinergic system was most complex during the metamorphic climax, with the appearance of positive cell bodies in the posterocentralis area of the thalamus, and in juvenile animals with the presence of perikarya in the ventral part of the medial pallium and within the central grey rhombencephali. In contrast to the adult frog, somatostatin neurons were not observed in the mesencephalon of tadpoles and juveniles.

Study of the interaction of dithranol with heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin in solution and in the solid state

The interaction between dithranol and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TMBCyD) has been investigated in aqueous solution containing isoascorbic acid (0.2% w/v) as antioxidant and in the solid state. The interaction in the solid state was studied by differential scanning calorimetry (DSC), infrared spectroscopy (IR), X-ray powder diffractometry (XPD) and a dissolution-rate method. The extent of complexation between the two substances was poor, as indicated by the low value of the slope of the linear part of the solubility curve. A phase diagram was constructed by measuring the thermal behaviour of various re-solidified physical mixtures of dithranol and of TMBCyD previously subjected to heating until melting of the TMBCyD. The loss of dithranol, owing to sublimation and degradation caused by the thermal treatment used, was less than 10%. In keeping with XPD and IR data, the phase diagram indicated that a complex was formed containing 13.7% dithranol (molar ratio 1:1) which had a congruent melting point at 164 degrees C. The drug dissolution rate from the 1:1 complex was measurable, unlike that of the corresponding physical mixture, and was significantly increased when the complex was dispersed in the glassy matrix of TMBCyD, as it was in re-solidified mixtures containing 2-7% dithranol. The results show that the solubility of dithranol is increased significantly as a consequence of its interaction with TMBCyD, despite the low extent of complexation between the two substances.

Melanin-concentrating hormone system in the brain of the lungfish Protopterus annectens

The neurochemical anatomy of the lungfish brain is of particular interest, because many features in these animals might be representative of the common ancestor of land vertebrates. In the present study, we have investigated the localization and biochemical characteristics of melanin-concentrating hormone (MCH)-immunoreactive material in the central nervous system of the African lungfish, Protopterus annectens. The most prominent group of MCH-immunoreactive cell bodies was found in the dorsal hypothalamus. Additional groups of MCH-immunoreactive perikarya were detected in the telencephalon within the medial and dorsal pallium, the medial subpallium, and the ventral part of the lateral subpallium. Brightly immunofluorescent nerve fibers were seen in the anterior olfactory nucleus, the ventral part of the medial pallium, the medial subpallium, and the anterior preoptic area. In the diencephalon, the hypothalamus and the medial region of the dorsal thalamus exhibited a dense accumulation of fibers. MCH-immunoreactive fibers were also found in the tectum and the tegmentum of the mesencephalon and within the reticular formation of the rhombencephalon. In the pituitary, several small groups of cells of the intermediate lobe showed a bright fluorescence. Reversed-phase high-performance liquid chromatography (HPLC) analysis of diencephalon and pituitary extracts resolved a major MCH-immunoreactive peak that coeluted with synthetic salmon MCH. The distribution of MCH in the brain of P. annectens suggests that, in lungfishes, this peptide may exert neuromodulator or neurotransmitter functions. The presence of MCH-like immunoreactivity in the intermediate lobe of the pituitary indicates that, in dipnoans, MCH may also act as a typical pituitary hormone.

Immunocytochemical localization of somatostatin and autoradiographic distribution of somatostatin binding sites in the brain of the African lungfish, Protopterus annectens

The anatomical distribution of somatostatin-immunoreactive structures and the autoradiographic localization of somatostatin binding sites were investigated in the brain of the African lungfish, Protopterus annectens. In general, there was a good correlation between the distribution of somatostatin-immunoreactive elements and the location of somatostatin binding sites in several areas of the brain, particularly in the anterior olfactory nucleus, the rostral part of the dorsal pallium, the medial subpallium, the anterior preoptic area, the tectum, and the tegmentum of the mesencephalon. However, mismatching was found in the mid-caudal dorsal pallium, the reticular formation, and the cerebellum, which contained moderate to high concentrations of binding sites and very low densities of immunoreactive fibers. In contrast, the caudal hypothalamus and the neural lobe of the pituitary exhibited low concentrations of binding sites and a high to moderate density of somatostatin-immunoreactive fibers. The present results provide the first localization of somatostatin in the brain of a dipnoan and the first anatomical distribution of somatostatin binding sites in the brain of a fish. The location of somatostatin-immunoreactive elements in the brain of P. annectens is consistent with that reported in anuran amphibians, suggesting that the general organization of the somatostatin peptidergic systems occurred in a common ancestor of dipnoans and tetrapods. The anatomical distribution of somatostatin-immunoreactive elements and somatostatin binding sites suggests that somatostatin acts as a hypophysiotropic neurohormone as well as a neurotransmitter and/or neuromodulator in the lungfish brain.

Primary structure of insulin from the african lungfish, Protopterus annectens

Among the extant Sarcopterygii, the interrelationship between the Dipnoi (lungfishes), Actinistia (coelacanths), and Tetrapoda (tetrapods) is controversial. Insulin has been purified from an extract of the pancreas of the African lungfish Protopterus annectens and its primary structure established as A-chain, Gly-Ile-Val-Glu-Gln-Cys-Cys-His-Lys-Pro10-Cys-Ser-Leu- Tyr -Glu-Leu-Glu-Asn-Tyr-Cys20-Asn-Val-Pro; and B-chain, Ala-Val-Leu-Asn-Gln-His-Leu-Cys-Gly-Ser10-His-Leu-Val- Glu- Ala-Leu-Tyr-Leu-Val-Cys20-Ala-Asp-Asn-Gly-Phe- Phe-Tyr-Lys-Pro-Ser30-Gly. Lungfish insulin contains unusual structural features, such as the dipeptide extension to the C-terminus of the A-chain and the substitution Arg --> Asn at position B-23 in the putative receptor binding region of insulin, which may be expected to influence appreciably its biological potency relative to mammalian insulins. Lungfish insulin also contains amino acid substitutions such as Gly --> Ala at position B-21, Glu --> Asp at position B-22, and a Lys --> Ser residue at position B-30, previously found in insulins from amphibia. This observation is consistent with paleontological data suggesting that lungfish and amphibia share a close phylogenetic relationship.

Detection of GnRH molecular forms in brains and gonads of the crested newt, Triturus carnifex

Gonadotrophin-releasing hormone (GnRH) immunoreactivity is detectable in the brain, ovary, and testis of the newt, Triturus carnifex, collected during February (reproductive phase), May, and July (nonreproductive phase). In the brain of May animals, chicken GnRH-II positive cell bodies are located within the terminal nerve, the anterior preoptic area, and the preoptic nucleus, which appears to be devoid of immunoreactive mammalian GnRH cell bodies. During February and July, both chicken GnRH-II and mammalian GnRH are detected only within the terminal nerve and anterior preoptic area. Generally, in the reproductive as well as the nonreproductive periods, chicken GnRH-II fibers are widely distributed in the brain; however, the distribution of fibers of both molecular forms suggests that they exert hypophysiotropic activity. High-pressure liquid chromatography (HPLC) coupled with radioimmunoassay indicates the presence of an early-eluting GnRH peak in brains and gonads but not in plasma. Using chicken GnRH-II antiserum, immunoreactivity is observed in spermatocytes, spermatozoa, and the external theca layer. Seasonal changes of the GnRH-like material are observed in both sexes, and its high concentration detectable during February is in good correlation with the timing of reproduction.

Immunocytochemical localization of atrial natriuretic factor and autoradiographic distribution of atrial natriuretic factor binding sites in the brain of the African lungfish, Protopterus annectens

The localization of atrial natriuretic factor (ANF)-immunoreactive elements was investigated in the brain of the African lungfish, Protopterus annectens, by using antisera raised against rat and human ANF(1-28). Concurrently, the distribution of ANF binding sites was studied by autoradiography using radioiodinated human ANF(1-28) as a tracer. In general, there was a good correlation between the distribution of ANF-immunoreactive structures and the location of ANF binding sites in several areas of the brain, particularly in the ventral part of the medial subpallium, the rostral preoptic region, the preoptic periventricular nucleus, the caudal hypothalamus, the neural lobe of the pituitary, and the mesencephalic tectum. In contrast, mismatching was observed in the pallium (which contained a high density of binding sites and a low concentration of ANF immunoreactive elements) as well as in the lateral subpallium and the medial region of the ventral thalamus, in which a low concentration of binding sites but a high density of ANF-immunoreactive fibers were detected. The present data provide the first localization of ANF-related peptides in the brain of dipnoans and the first anatomical distribution of ANF binding sites in the brain of fish. The results show that the ANF peptidergic systems of P. annectens exhibit similarities with those previously described in the frog Rana ridibunda, supporting the existence of relationships between dipnoans and amphibians. The location of ANF-like immunoreactivity and the distribution of ANF binding sites suggest that ANF-related peptides may act as hypothalamic neurohormones as well as neurotransmitters and/or neuromodulators in the lungfish brain.

Distribution of FMRFamide-like immunoreactivity in the brain and pituitary of Rana esculenta during development

Developmental aspects of the distribution of FMRFamide (Phe-Met-Arg-Phe-NH2) immunoreactivity (ir) were investigated by indirect immunofluorescence in the brain, pituitary and terminal nerve of the frog, Rana esculenta. Soon after hatching. FMRFamide neurons were found in the proximal terminal nerve, mediobasal olfactory bulb, caudal dorsolateral pallium, diagonal band of Broca, anterior preoptic area, suprachiasmatic area, thalamus, infundibulum, and developing pituitary. FMRFamide fibers were present in the olfactory epithelium, terminal nerve, olfactory bulbs, dorsal and midventral telencephalon, epiphysis, mediolateral thalamus, pretectal gray, optic tectum, infundibulum, posterior interpeduncular nucleus-tegmentum area, and rostral rhombencephalon. During successive developmental stages, ir neurons were no longer observed in the dorsal telencephalon and pituitary. In late larval stages, ir neurons appeared in the medial septal area, and ir fibers in the cerebellum and torus semicircularis. At the same time, the frequency of ir neurons increased progressively in the anterior preoptic area, suprachiasmatic area and infundibulum. FMRFamide-ir neurons were never revealed in mesencephalon and rhombencephalon. Numerous ir fibers terminated in the median eminence and intermediate lobe of the pituitary. The adult pattern of distribution of FMRFamide-ir elements in the brain was achieved during the postmetamorphic development. In light of the existing literature, the possible placodal origin of forebrain-located FMRFamide neurons is briefly discussed.

Neuropeptide Y: localization in the brain and pituitary of the developing frog (Rana esculenta)

The immunohistochemical localization of neuropeptide Y (NPY)-like peptide has been investigated in the peripheral terminal nerve, brain and pituitary of the frog, Rana esculenta, during development. Soon after hatching, a rather simple NPY-immunoreactive (-ir) neuronal system is present, with elements located mainly in the diencephalon. When hind limbs appear and develop, the NPY-neuronal system undergoes considerable elaboration and NPY-ir perikarya appear in several regions of the telencephalon (dorsal, medial, and lateral pallium; medial septum; medioventral telencephalon; anterior preoptic area), diencephalon (ventromedial, central and posterior thalamic nuclei; suprachiasmatic nucleus; infundibulum), mesencephalon (anteroventral mesencephalic tegmentum), and rhombencephalon (central grey; area of the cerebellar and vestibular nuclei). The frequency of NPY-ir neurons increases during larval development, and then decreases in the anterior preoptic area during the metamorphic climax. Dense plexuses of NPY-ir fibers are formed in several brain areas. NPY-ir fibers are found in the peripheral terminal nerve, and ir-neurons through its course along the ventromedial surface of the olfactory bulbs. NPY-ir fiber projections to the median eminence and pars intermedia derive mainly from the ventral infundibular group of NPY-ir neurons, with a contribution from the suprachiasmatic group of NPY neurons. NPY and carboxyl terminal flanking peptide of proneuropeptide Y coexist in the same neurons throughout the brain. The ontogenetic pattern of NPY-ir neuronal system in the brain of Rana esculenta is remarkably different than that reported for Xenopus laevis.

Immunoreactive Phe-Met-Arg-Phe-NH2-like peptides in the brain of the antarctic icefish, Chionodraco hamatus

The distribution of Phe-Met-Arg-Phe-NH2 (FMRFamide)-like immunoreactive peptides was investigated in the brain of the antarctic icefish, Chionodraco hamatus, using the indirect immunofluorescence technique. Three main groups of immunoreactive perikarya were respectively localized in the nucleus entopeduncularis of the telencephalon, the nucleus preopticus periventricularis of the hypothalamus, and within the nucleus oculomotorius of the mesencephalon. Delicate FMRFamide positive nerve fibers were distributed in several brain regions of the forebrain and brainstem. In particular, these fibers densely innervated the caudal part of the dorsomedial pallium, the hypothalamus, the thalamus, the mesencephalic tegmentum and the optic tectum. The distribution pattern of the FMRFamide-like immunoreactivity was compared with that reported in previous studies in other teleost species. The anatomical organization of the FMRFamide-like immunoreactive peptidergic system in the brain of Chionodraco hamatus suggests that a FMRFamide-like peptide may play a role as a neuromodulator in fish adapted to the extreme Antarctic environment.

Urotensin II in the central nervous system of the frog Rana ridibunda: immunohistochemical localization and biochemical characterization

Urotensin II (UII) is traditionally regarded as a product of the neurosecretory cells in the caudal portion of the spinal cord of jawed fishes. A peptide related to UII has been recently isolated from the frog brain, thereby providing the first evidence that UII is also present in the central nervous system of a tetrapod. In the present study, we have investigated the distribution of UII-immunoreactive elements in the brain and spinal cord of the frog Rana ridibunda by immunofluorescence using an antiserum directed against the conserved cyclic region of the peptide. Two distinct populations of UII-immunoreactive perikarya were visualized. The first group of positive neurons was found in the nucleus hypoglossus of the medulla oblongata, which controls two striated muscles of the tongue. The second population of immunoreactive cell bodies was represented by a subset of motoneurons that were particularly abundant in the caudal region of the cord (34% of the motoneuron population). The telencephalon, diencephalon, mesencephalon, and metencephalon were totally devoid of UII-containing cell bodies but displayed dense networks of UII-immunoreactive fibers, notably in the thalamus, the tectum, the tegmentum, and the granular layer of the cerebellum. In addition, a dense bundle of long varicose processes projecting rostrocaudally was observed coursing along the ventral surface of the brain from the midtelencephalon to the medulla oblongata. Reversed-phase high-performance liquid chromatography analysis of frog brain, medulla oblongata, and spinal cord extracts revealed that, in all three regions, UII-immunoreactive material eluted as a single peak which exhibited the same retention time as synthetic frog UII. Taken together, these data indicate that UII, in addition to its neuroendocrine functions in fish, is a potential regulatory peptide in the central nervous system of amphibians.

Localization of GnRH molecular forms in the brain, pituitary, and testis of the frog, Rana esculenta

In the amphibian brain four molecular forms of GnRH have been identified so far: mammalian GnRH (m- and hydroxyproline9m-), chicken II GnRH (cII), and a salmon (s) GnRH-like peptide. In Rana esculenta, cII- and s-GnRH-like molecules have been partially characterized in the brain extracts using HPLC combined with radioimmunoassay. Moreover, since cII-GnRH-like material has been detected in Rana esculenta testis, the present study describes the localization of the above peptides in the brain and testis of the frog. Immunoreactive cII-GnRH and m-GnRH neurons and fibers were identified in the anterior preoptic area (APOA) and in the median septal area (MSA). A population of cells located on the dorsal side of the caudal preoptic region was also stained. Immunopositive fibers were seen to overlap the median eminence before ending within the pars nervosa. Moreover, densely packed fibers made close contact with the vascular complex in the median eminence. Conversely, immunoreactive s-GnRH-like material was absent in APOA and MSA, but weakly scattered elements were detected by the anti-s-GnRH serum in the dorsal side of the caudal preoptic region. Using m-GnRH antiserum, a strong immunopositivity was observed in the median eminence but not within the pars nervosa, indicating that, besides cII-GnRH and s-GnRH-like material, also m-GnRH-like material is present in Rana esculenta brain. In the testis, cells of the interstitial and germinal compartment were detected by anti-cII-GnRH during different periods of the annual cycle. In particular, in October and February interstitial tissue was intensely stained, coinciding with periods of increased androgen production and the onset of the new spermatogenic wave, respectively.